Slotted stiffening member for electrode lead insertion

ABSTRACT

An illustrative stiffening member includes a body configured to integrate with a portion of an electrode lead so as to maintain the portion of the electrode lead in a substantially linear configuration in an absence of a flexure force. The stiffening member includes a plurality of slots distributed along the body and configured to bias the body, in a presence of the flexure force, to flex inwardly on a first side of the body that is closer to electrodes of the electrode lead than is a second side opposite the first side. The stiffening member also includes an orientation retainer coupled to the body and configured to interface with the electrode lead to maintain, while the body is integrated with the portion of the electrode lead, the first side of the body closer to the electrodes than the second side of the body.

RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/767,969, filed May 28, 2020, which claimspriority to PCT International Application No. PCT/US2017/064035, filedNov. 30, 2017, each of which is hereby incorporated by reference in itsentirety.

BACKGROUND INFORMATION

Cochlear implant systems are used to provide, restore, and/or improvehearing loss suffered by cochlear implant patients who use the cochlearimplant systems. In operation, typical cochlear implant systems includeone or more external components such as a microphone, a sound processor,and a headpiece that interoperate to control and direct one or moreinternal (e.g., implanted) components such as a cochlear implant and anelectrode lead having a plurality of electrodes disposed along theelectrode lead.

The electrode lead may be surgically implanted into the patient'scochlea to allow the plurality of electrodes disposed along theelectrode lead to apply electrical stimulation generated by the cochlearimplant to different areas of the cochlear tissue. Unfortunately, thesurgical procedure by way of which an electrode lead is inserted into apatient's cochlea (referred to herein as an “insertion procedure”) maybe a delicate and difficult procedure to perform. Even when performedwith great care and skill, an insertion procedure may result in traumato the cochlea (e.g., which may lead to a reduction in residual hearing,pain or discomfort experienced by the patient, etc.), suboptimalelectrode lead placement (e.g., which may lead to suboptimal cochlearimplant system performance, etc.), and/or other undesirable results.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings illustrate various embodiments and are a partof the specification. The illustrated embodiments are merely examplesand do not limit the scope of the disclosure. Throughout the drawings,identical or similar reference numbers designate identical or similarelements.

FIG. 1 illustrates an exemplary cochlear implant system according toprinciples described herein.

FIG. 2 illustrates a schematic structure of the human cochlea accordingto principles described herein.

FIG. 3 illustrates an exemplary electrode lead assembly including anelectrode lead and a slotted stiffening member for facilitating aninsertion of the electrode lead into a cochlea of a patient according toprinciples described herein.

FIG. 4 illustrates an implementation of the slotted stiffening member ofFIG. 3 that implements a predetermined stiffness profile according toprinciples described herein.

FIG. 5 illustrates an exemplary electrode lead assembly including anelectrode lead and a slotted stiffening member implemented as astiffening sleeve permanently overmolded along a portion of theelectrode lead according to principles described herein.

FIG. 6A illustrates a plurality of exemplary compression slots and aplurality of exemplary strain relief slots distributed along a body ofan exemplary slotted stiffening member while the body is in asubstantially linear configuration in an absence of a flexure force onthe body according to principles described herein.

FIG. 6B illustrates the plurality of exemplary compression slots and theplurality of exemplary strain relief slots of FIG. 6A while the body ofthe slotted stiffening member is in a flexed configuration in a presenceof the flexure force on the body according to principles describedherein.

FIG. 7A illustrates an exemplary plurality of compression slots andstrain relief slots that may be included on a slotted stiffening membersuch as the stiffening member of FIG. 3 according to principlesdescribed herein.

FIG. 7B illustrates another exemplary plurality of compression slots andstrain relief slots that may be included on a slotted stiffening membersuch as the stiffening member of FIG. 3 according to principlesdescribed herein.

FIG. 7C illustrates yet another exemplary plurality of compression slotsand strain relief slots that may be included on a slotted stiffeningmember such as the stiffening member of FIG. 3 according to principlesdescribed herein.

FIG. 7D illustrates yet another exemplary plurality of compression slotsand strain relief slots that may be included on a slotted stiffeningmember such as the stiffening member of FIG. 3 according to principlesdescribed herein.

FIG. 8A illustrates an implementation of the electrode lead assembly ofFIG. 3 flexing under a flexure force present as a result of contactbetween tissue of a cochlea of a patient and an electrode leadintegrated with the stiffening member according to principles describedherein.

FIG. 8B illustrates an implementation of the electrode lead assembly ofFIG. 3 flexing under a flexure force present as a result of tensionapplied to a pull wire coupled with a distal tip of the stiffeningmember according to principles described herein.

FIG. 9A illustrates an exemplary orientation retainer coupled to thebody of an exemplary slotted stiffening member at a proximal end of thebody according to principles described herein.

FIG. 9B illustrates the orientation retainer of FIG. 9A interfacing withan exemplary electrode lead to maintain a first side of the stiffeningmember to be closer to electrodes of the electrode lead than a secondside opposite the first side according to principles described herein.

DETAILED DESCRIPTION

Implementations of a slotted stiffening member for facilitating aninsertion of an electrode lead into a cochlea of a patient are describedherein. For example, as will be described in more detail below, astiffening member (e.g., a stylet, a stiffening sleeve, etc.) may beemployed to facilitate an insertion, into a cochlea of a cochlearimplant patient, of an electrode lead having a plurality of electrodes.Such a stiffening member may include an elongate body having a firstside and a second side opposite the first side. The body of thestiffening member may be configured to integrate with a portion of theelectrode lead along a length of the electrode lead so as to maintainthe portion of the electrode lead in a substantially linearconfiguration in an absence of a flexure force on the body. Forinstance, while the body of the stiffening member is integrated with theelectrode lead (e.g., by being encapsulated within a lumen of theelectrode lead, by being overmolded over the portion of electrode lead,etc.), the first side of the body may be configured to be closer to theelectrodes than the second side. The stiffening member may furtherinclude a plurality of compression slots distributed along the firstside of the body and a plurality of strain relief slots distributedalong the second side of the body. The plurality of compression slotsmay be configured to compress, in a presence of the flexure force, so asto bias the body of the stiffening member to flex in an inwarddirection. Similarly, the plurality of strain relief slots may beconfigured to expand in the presence of the flexure force so as tocomplement the plurality of compression slots in biasing the body toflex in the inward direction.

In some examples, as will be described in more detail below, a pluralityof compression slots included on a slotted stiffening member mayimplement a predetermined stiffness profile. For instance, by beingdistributed along the first side of the body of the slotted stiffeningmember in a non-uniform distribution, the plurality of compression slotsmay make certain portions of the stiffening member relatively flexible(e.g., prone to flex in the presence of a flexure force) while makingother portions of the stiffening member relatively stiff (e.g., not asprone to flex in the presence of the flexure force) in accordance withthe predetermined stiffness profile. Similarly, a plurality of strainrelief slots included on the slotted stiffening member may furtherimplement the predetermined stiffness profile by being distributed alongthe second side of the body in a non-uniform distribution thatcorresponds to the non-uniform distribution of the plurality ofcompression slots. Along with being distributed in the non-uniformdistribution along the body, the compression slots and/or strain reliefslots may further implement the predetermined stiffness profile byincluding a difference in slot size among different compression slots orstrain relief slots, a difference in slot type among differentcompression slots or strain relief slots, or in any other manner as mayserve a particular implementation.

Various benefits may be provided by slotted stiffening members forfacilitating insertion of electrode leads into cochleae of patientsdescribed herein. In particular, these slotted stiffening members mayimprove the outcome of electrode lead insertion procedures by makingsuch procedures easier to perform consistently and successfully.

As mentioned above, electrode lead insertion procedures may typically beassociated with a relatively large degree of risk of cochlear trauma dueto the delicate nature of the cochlea and the difficulty of theinsertion procedure. For instance, in examples where an electrode leadbeing inserted is overly stiff, the electrode lead may scrape the tissueof the cochlea rather than flexing when coming into contact with thetissue. In some cases, the electrode lead may even translocate from onecochlear chamber to another by penetrating a wall of the cochlearchamber into which the electrode lead is being inserted. Such trauma mayresult in a loss of residual hearing, pain and discomfort, and/or othernegative consequences for the patient. Conversely, in examples where anelectrode lead being inserted is overly flexible or limp, the electrodelead may be uncompliant and difficult to insert due to undesirabletwisting, buckling, and so forth. In some examples, this resistance tocomply with a surgeon's attempts to insert the electrode lead maysimilarly result in translocation or other cochlea trauma as excessiveforce may be applied to the electrode lead in an attempt to force theelectrode lead to comply.

Fortunately, slotted stiffening members described herein may cause anelectrode lead to have an optimized stiffness to flex when in contactwith cochlear tissue (e.g., without causing trauma to the tissue) whilenot flexing so easily that the electrode lead becomes uncompliant anddifficult to control (e.g., thus possibly requiring additional force toinsert). Additionally, because the stiffness of a slotted stiffeningmember may be controlled by way of various factors such as slotdistribution, slot size, slot type, and so forth as described above,slotted stiffening members may be customized and/or fine-tuned toimplement any stiffness as may serve a particular implementation. Insome examples, as mentioned above, slotted stiffening members may evenbe characterized by different stiffness gradients at different portionsof the stiffening members in accordance with non-uniform predeterminedstiffness profiles. For example, a slotted stiffening member may be madeto be stiffer at portions where stiffness is desirable (e.g., near adistal tip of the electrode lead) and more flexible at portions whereflexibility is desirable (e.g., near portions of the electrode leadconfigured to rest along certain curves of the cochlea). Moreover,because of the complementary placement of compression slots and strainrelief slots on opposing sides of the slotted stiffening members,electrode leads may be biased (e.g., constrained, limited, etc.) to flexin only one direction (e.g., inwardly) or two directions (e.g., inwardlyor outwardly), rather than to freely flex and twist in any directionincluding lateral directions that may be undesirable.

As a result of optimized and customized stiffness profiles made possibleby slotted stiffening members described herein, as well as directionalflexing and other benefits made possible by these slotted stiffeningmembers, electrode lead insertion procedures involving slottedstiffening member described herein may be performed by hand with minimalor no additional tools. For instance, in certain examples, an insertionprocedure may be performed by hand and without special tools by allowingthe electrode lead to gently and unidirectionally flex as a result offlexure force from contact with the tissue of the cochlea. In otherexamples, an insertion procedure may be performed by hand using minimaltools such as a tool to facilitate control of a steering pull wireincluded within the stiffening member and configured to apply a flexureforce on the stiffening member to thereby cause the stiffening member toflex while avoiding contact with the cochlear tissue.

Moreover, all of these benefits may be provided by slotted stiffeningmembers that are relatively inexpensive and straightforward tomanufacture. For example, rather than being made of costly noble metalssuch as platinum, slotted stiffening members described herein may beconstructed from standard surgical stainless steel tubing or othersuitable materials.

Additionally, the materials from which slotted stiffening membersdescribed herein may be constructed may retain their shape (e.g.,without plastically deforming) when flexed as described herein.Accordingly, while such stiffening members may remain permanentlyintegrated with the electrode lead after the insertion procedure in someexamples, in other examples, it may be relatively straightforward towithdraw the stiffening members subsequent to the insertion procedure ifthat should be desirable. This may be advantageous in comparison tocertain conventional stiffening members that plastically deform whenflexed and thus would risk upsetting the configuration of an electrodelead within the cochlea if withdrawn subsequent to the insertionprocedure.

Various embodiments will now be described in more detail with referenceto the figures. The disclosed systems and methods may provide one ormore of the benefits mentioned above and/or various additional and/oralternative benefits that will be made apparent herein.

In order to illustrate an exemplary context in which a slottedstiffening member for facilitating an insertion of an electrode leadinto a cochlea of a patient may operate, FIG. 1 depicts an exemplarycochlear implant system 100. As shown, cochlear implant system 100 mayinclude a microphone 102, a sound processor 104, a headpiece 106 havinga coil disposed therein, a cochlear implant 108, and an electrode lead110 including a plurality of electrodes 112. Additional or alternativecomponents may be included within cochlear implant system 100 as mayserve a particular implementation.

As shown, cochlear implant system 100 may include various componentsconfigured to be located external to a patient including, but notlimited to, microphone 102, sound processor 104, and headpiece 106.Cochlear implant system 100 may further include various componentsconfigured to be implanted within the patient including, but not limitedto, cochlear implant 108 and electrode lead 110.

Microphone 102 may be configured to detect audio signals presented tothe patient (e.g., also referred to herein as a user of cochlear implantsystem 100). Microphone 102 may be implemented in any suitable manner.For example, microphone 102 may include a microphone that is configuredto be placed within the concha of the ear near the entrance to the earcanal, such as a T-MIC™ microphone from Advanced Bionics. Such amicrophone may be held within the concha of the ear near the entrance ofthe ear canal by a boom or stalk that is attached to an ear hookconfigured to be selectively attached to sound processor 104.Additionally or alternatively, microphone 102 may be implemented by oneor more microphones disposed within headpiece 106, one or moremicrophones disposed within sound processor 104, one or morebeam-forming microphones, and/or any other suitable microphone as mayserve a particular implementation.

Sound processor 104 may represent a sound processor having a processingcomponent (e.g., including various computing components such as aprocessor, memory, communication interfaces, etc.), a battery component,and, in certain implementations, one or more other components such as anearhook component, a cable component (e.g., a cable communicativelycoupling sound processor 104 with headpiece 106), and so forth. Soundprocessor 104 may be configured to process an audio signal (e.g., anacoustic audio signal detected by microphone 102, an electrical audiosignal input by way of an auxiliary audio input port or a Clinician'sProgramming Interface (“CPI”) device, etc.) and to direct stimulationrepresentative of the audio signal to be presented to a user of cochlearimplant system 100 (e.g., a cochlear implant patient). For example, thestimulation representative of the audio signal and directed by the soundprocessor component to be presented to the patient may be electricalstimulation generated by cochlear implant 108 and applied by electrodes112 on electrode lead 110 implanted within the user.

Sound processor 104 may be configured to direct cochlear implant 108 togenerate and apply electrical stimulation (also referred to herein as“stimulation current”) representative of an audio signal to the patient.For example, sound processor 104 may direct cochlear implant 108 toapply electrode stimulation to one or more stimulation sites associatedwith an auditory pathway (e.g., the auditory nerve) of the patient.Exemplary stimulation sites include, but are not limited to, one or morelocations within the cochlea, the cochlear nucleus, the inferiorcolliculus, and/or any other nuclei in the auditory pathway.

Sound processor 104 may process the audio signal in accordance with aselected sound processing strategy or program to generate appropriatestimulation parameters for controlling cochlear implant 108. Soundprocessor 104 may be housed within any suitable housing. For example,sound processor 104 may be implemented as a behind-the-ear (“BTE”) unit,a body worn unit, or the like.

In some examples, sound processor 104 may wirelessly transmitstimulation parameters (e.g., in the form of data words included in aforward telemetry sequence) and/or power to cochlear implant 108 by wayof a wireless communication link 114 between headpiece 106 and cochlearimplant 108 (e.g., a wireless link between a coil disposed withinheadpiece 106 and a coil included within or coupled to cochlear implant108). To this end, headpiece 106 may be communicatively coupled to soundprocessor 104 and may include an antenna (e.g., a coil and/or one ormore wireless communication components) configured to facilitateselective wireless coupling of sound processor 104 to cochlear implant108. Additionally or alternatively, headpiece 106 may be used toselectively and wirelessly couple any other external device (e.g., abattery charger, etc.) to cochlear implant 108. Headpiece 106 may beconfigured to be affixed to the patient's head and positioned or alignedsuch that an antenna housed within headpiece 106 is communicativelycoupled to a corresponding implantable antenna (which may also beimplemented by a coil and/or one or more wireless communicationcomponents) included within or otherwise associated with cochlearimplant 108. In this manner, stimulation parameters and/or power signalsmay be wirelessly transferred between sound processor 104 and cochlearimplant 108 via wireless communication link 114 transcutaneously.

Cochlear implant 108 may include any type of implantable stimulator thatmay be used in association with systems described herein. For example,cochlear implant 108 may be implemented by an implantable cochlearstimulator. In some alternative implementations, cochlear implant 108may include a brainstem implant and/or any other type of cochlearimplant that may be implanted within a patient and configured to applystimulation to one or more stimulation sites located along an auditorypathway of a patient.

Electrode lead 110 may include an array of electrodes 112 disposed on adistal portion of electrode lead 110 and that are configured to beinserted into the cochlea to stimulate the cochlea after the distalportion of electrode lead 110 is inserted into the cochlea. As shown,electrode lead 110 may be pre-curved so as to properly fit within thespiral shape of the cochlea. As such, electrodes 112 may all be disposedon one side of the electrode lead (e.g., the inward side in whichelectrode lead 110 is pre-curved, as shown). It will be understood thatone or more other electrodes (e.g., including a ground electrode, notexplicitly shown) may also be disposed on other parts of electrode lead110 (e.g., on a proximal portion of electrode lead 110) to, for example,provide a current return path for stimulation current generated byelectrodes 112 as it remains external to the cochlea while electrodelead 110 is disposed within the cochlea.

In some examples, cochlear implant 108 may be configured to generateelectrical stimulation representative of an audio signal processed bysound processor 104 (e.g., an audio signal detected by microphone 102)in accordance with one or more stimulation parameters transmittedthereto by sound processor 104. Cochlear implant 108 may be furtherconfigured to apply the electrical stimulation to one or morestimulation sites (e.g., one or more intracochlear locations) within thepatient by way of electrodes 112 disposed along electrode lead 110. Insome examples, cochlear implant 108 may include a plurality ofindependent current sources each associated with a channel defined byone or more of electrodes 112. In this manner, different stimulationcurrent levels may be applied to multiple stimulation sitessimultaneously by way of multiple electrodes 112.

FIG. 2 illustrates a schematic structure of the human cochlea 200 intowhich electrode lead 110 may be inserted. As shown in FIG. 2, cochlea200 is in the shape of a spiral beginning at a base 202 and ending at anapex 204. Within cochlea 200 resides auditory nerve tissue 206 (alsoreferred to herein as cochlear tissue), which is denoted by Xs in FIG.2. The auditory nerve tissue 206 is organized within the cochlea 200 ina tonotopic manner. Relatively low frequencies are encoded at or nearapex 204 of cochlea 200 (referred to as an “apical region”) whilerelatively high frequencies are encoded at or near base 202 (referred toas a “basal region”). Hence, electrical stimulation applied by way ofelectrodes disposed within the apical region (i.e., “apical electrodes”)may result in the patient perceiving relatively low frequencies andelectrical stimulation applied by way of electrodes disposed within thebasal region (i.e., “basal electrodes”) may result in the patientperceiving relatively high frequencies. The delineation between theapical and basal electrodes on a particular electrode lead may varydepending on the insertion depth of the electrode lead, the anatomy ofthe patient's cochlea, and/or any other factor as may serve a particularimplementation.

As mentioned above, a cochlear implant system such as cochlear implantsystem 100 may be used by a patient subsequent to an insertion procedurewhereby an electrode lead such as electrode lead 110 is inserted into acochlea of a patient such as cochlea 200. To facilitate such aninsertion procedure, it may be desirable for the electrode lead to bestiff enough to be maneuvered into the cochlea without buckling,snagging, and/or encountering other issues described above. At the sametime, it also may be desirable for the electrode lead to be flexibleenough to easily flex when a significant flexure force is applied to theelectrode lead (e.g., such as from making contact with cochlear tissue).For example, it would be desirable for the electrode lead to flex andgive way to the cochlear tissue in the presence of such a force ratherthan to translocate through the tissue or otherwise cause trauma to thetissue. Moreover, it may further facilitate the insertion procedure ifthe electrode lead is able to flex in certain directions (e.g., in aninward direction such as illustrated in FIG. 1) without twisting orflexing in other directions (e.g., in lateral directions that do notconform to the shape of the cochlea, etc.).

To this end, an electrode lead assembly that includes a slottedstiffening member may be employed that meets these and other criteriafor facilitating electrode lead insertion procedures. Specifically, anelectrode lead assembly may include an electrode lead having an elongatelead body with a first side and a second side opposite the first side, aplurality of electrodes disposed along the first side of the lead body,and a stiffening member configured to facilitate an insertion of theelectrode lead into a cochlea of a patient. The stiffening member mayintegrate with a portion of the electrode lead along a length of theelectrode lead so as to maintain the portion of the electrode lead in asubstantially linear configuration in an absence of a flexure force onthe stiffening member. Additionally, the stiffening member may include aplurality of compression slots distributed along a first side of thestiffening member that corresponds to the first side of the lead body,and a plurality of strain relief slots distributed along a second sideof the stiffening member that corresponds to the second side of the leadbody. The plurality of compression slots may be configured to compress(e.g., in a presence of the flexure force) so as to bias the stiffeningmember to flex in an inward direction. Similarly, the plurality ofstrain relief slots may be configured to expand (e.g., in the presenceof the flexure force) so as to complement the plurality of compressionslots in biasing the stiffening member to flex in the inward direction.

To illustrate, FIG. 3 depicts an exemplary electrode lead assembly 300including an electrode lead and a slotted stiffening member forfacilitating an insertion of the electrode lead into a cochlea of apatient. Specifically, FIG. 3 illustrates electrode lead assembly 300 ina substantially linear (e.g., straightened) configuration such aselectrode lead assembly 300 may be in prior to an insertion procedure inwhich electrode lead assembly 300 is inserted into a cochlea of apatient. As shown, electrode lead assembly 300 includes an electrodelead 302, a distal portion 304 of which is depicted in FIG. 3. Whiledistal portion 304 includes a distal tip 306 of electrode lead 302, itwill be understood that a proximal portion 308 of electrode lead 302 isnot explicitly illustrated in FIG. 3 but rather is represented by anomission symbol shown at a most proximal point on the portion ofelectrode lead 302 illustrated. It will be understood that proximalportion 308 of electrode lead 302 may extend past distal portion 304 tocouple with a cochlear implant such as cochlear implant 108 beyond theomission symbol.

Electrode lead 302 may include an elongate lead body 310 having a firstside and a second side opposite the first side, as labeled in FIG. 3.Along the first side of lead body 310, a plurality of electrodes 312 maybe disposed, including a most distal electrode 314 and most proximalelectrode 316. Because electrode lead 302 is configured to be insertedinto a cochlea with distal end 306 entering first, electrodes 312 nearproximal portion 308 may be referred to as basal electrodes, withelectrode 316 being referred to as a most basal electrode. Similarly,electrodes near distal tip 306 may be referred to as apical electrodes,with electrode 314 being referred to as a most apical electrode. Whileadditional electrodes (e.g., such as a ground electrode) may be includedon proximal portion 308 (not shown), it will be understood thatelectrodes 312 disposed along the first side of lead body 310 may not bedistributed along the entire length of the entire first side of leadbody 310, but, rather, may be limited to distal portion 304, as shown.In a similar way, it will be understood that a slotted stiffening membermay only integrate with a certain portion of electrode lead 302 (e.g.,rather than integrating with an entire length of electrode lead 302),and/or that a slotted portion of the slotted stiffening member maycorrespond only to a certain portion of electrode lead 302 (e.g., distalportion 304) while other portions of the slotted stiffening member(e.g., portions corresponding to proximal portion 308 of electrode lead302) may not include slots or other such features.

In the example of FIG. 3, electrode lead 302 is shown to further includea lumen 318 into which a stylet may be inserted. As such, a slottedstiffening member implemented as a stylet 320 may be encapsulated withinlumen 318 to facilitate an insertion procedure of electrode leadassembly 300 into a cochlea of a patient. In certain examples, stylet320 may be configured to be temporarily encapsulated in lumen 318 ofelectrode lead 302 so as to be removable from lumen 318 after a surgicalinsertion of electrode lead 302 into the cochlea of the patient.Conversely, in other examples, stylet 320 may be configured to bepermanently encapsulated in lumen 318 of electrode lead 302 so as toremain encapsulated in lumen 318 after the surgical insertion ofelectrode lead 302 into the cochlea of the patient.

As shown in FIG. 3, stylet 320 may include an elongate body 322 having afirst side and a second side opposite the first side and configured tobe encapsulated within lumen 318 of electrode lead 302 so as to maintainelectrode lead 302 in a substantially linear configuration in an absenceof a flexure force on body 322. The first side of body 322 correspondsto the first side of the electrode lead and, as such, is configured tobe closer to electrodes 312 than the second side of body 322 while body322 is encapsulated within lumen 318 of electrode lead 302.

Body 322 may be constructed of any suitable material with any suitableplasticity limits. For instance, in some implementations, body 322 ofstylet 320 may be constructed of a material that will plastically deformas body 322 flexes in the presence of a flexure force. In other words,even after the flexure force is removed, these implementations of stylet320 may not return to the substantially linear configuration but may atleast partially retain the flexed configuration. In otherimplementations, body 322 of stylet 320 may be constructed of a materialthat does not plastically deform (e.g., does not reach a limit ofplasticity) as a result of an inward flexing of body 322 due to thepresence of the flexure force, even when stylet 320 is inwardly flexedto a relatively large angle of deflection (e.g., up to 270°, up to 360°,etc.). In other words, even after such implementations of stylet 320have been inwardly flexed significantly in the presence of a flexureforce, body 322 may return to the substantially linear configurationillustrated in FIG. 3 upon removal of the flexure force causing theinward flexing. As mentioned above, such implementations may beadvantageous if it is desirable for stylet 320 to be removed from lumen318 after electrode lead assembly 300 has been inserted into thecochlea.

With these factors in mind, any of various suitable materials may beused to construct stylet 320. For example, a surgical grade stainlesssteel material (e.g., stainless steel surgical tubing, etc.) or apolymer material (e.g., polyimide tubing, PTFE tubing, etc.) may beused. Additionally, a coating may be applied to the material from whichstylet 320 is constructed to reduce friction, protect the material, andso forth. For instance, a PARYLENE coating, PTFE coating, or othersuitable coating may be employed.

As shown in FIG. 3, stylet 320 may include a plurality of compressionslots 324 distributed along the first side of body 322, and a pluralityof strain relief slots 326 distributed along the second side of body322. The plurality of compression slots 324 may be configured tocompress, in a presence of the flexure force, so as to bias the body toflex in an inward direction (e.g., to curl inward on the first side withthe electrodes as illustrated by electrode lead 110 in FIG. 1). At thesame time, the plurality of strain relief slots may be configured toexpand, in the presence of the flexure force, so as to complement theplurality of compression slots in biasing the body to flex in the inwarddirection.

Slots 324 and 326 may be formed in any manner as may serve a particularimplementation. For example, slots 324 and 326 may be formed in tubingmaterial by way of a micromachining process, by laser cutting, or thelike. In other examples, slots 324 and 326 may be formed by way of amolding process or in another suitable manner.

As shown, the plurality of compression slots 324 and the plurality ofstrain relief slots 326 are distributed along the first and second sidesof the body, respectively, in respective uniform distributions thatcorrespond to a uniform stiffness profile. Each plurality of slotsincludes slots that are all of an identical size and type, furthercontributing to a uniform stiffness throughout stylet 320. While suchuniform slot distribution, size, and type may be advantageous in certainimplementations, other implementations may include at least somevariance in slot distribution, size, and/or type in order to implement anon-uniform stiffness profile. For example, the plurality of compressionslots 324 included in stylet 320 may implement a predetermined stiffnessprofile by being distributed along the first side of body 322 in anon-uniform distribution in accordance with the predetermined stiffnessprofile, and the plurality of strain relief slots 326 may furtherimplement the predetermined stiffness profile by being distributed alongthe second side of the body in a non-uniform distribution thatcorresponds to the non-uniform distribution of the plurality ofcompression slots 324.

To illustrate, FIG. 4 shows an implementation of stylet 320 thatimplements a predetermined stiffness profile by including variance inslot distribution, size, and type. As shown, three different portions ofbody 322 of stylet 320, each characterized by different configurationsof slots 324 and/or 326, are labeled in FIG. 4. Portion 402 (includingtwo sub-portions 402-1 and 402-2) includes slots 324 and 326 that aresimilar in type, size, and spacing to the uniform stiffness profileillustrated in FIG. 3. However, different parts of the non-uniformstiffness profile are implemented by a portion 404 and a portion 406 ofstylet 320.

As compared to portion 402, portion 404 includes a difference in slotsize among different compression slots 324 in the plurality ofcompression slots 324 and a difference in slot size among differentstrain relief slots 326 in the plurality of strain relief slots 326while generally keeping the respective slot types (e.g., the generalshape of each slot) the same. Additionally, slots 324 and 326 in portion404 are distributed with greater spacing in between slots as compared tothe spacing in portion 402. As a result of either or both of thesedifferences, portion 404 may be stiffer than portion 402.

In contrast, as compared to portion 402, portion 406 includes adifference in slot type among different compression slots 324 in theplurality of compression slots 324 as well as a difference in slot typeamong different strain relief slots 326 in the plurality of strainrelief slots 326. Specifically, as will be described in more detailbelow, the compression slots 324 and strain relief slots 326 in portion406 may be symmetrical so as to bias portion 406 to flex in either aninward direction or an outward direction while still limiting theability of portion 406 to flex or twist in a lateral direction.Including a symmetrical portion such as portion 406 (i.e., a portion inwhich compression slots 324 and strain relief slots 326 are sized andshaped in the same way to facilitate bidirectional flexing) along withasymmetrical portions such as portions 402 and/or 404 (i.e., portions inwhich compression slots 324 and strain relief slots 326 are sized andshaped differently from one another to facilitate only unidirectionalflexing) may be beneficial in certain implementations.

FIGS. 3 and 4 have illustrated and described different aspects ofimplementations of stylet 320 to illustrate one type of slottedstiffening member that may be used in an electrode lead assembly such aselectrode lead assembly 300. However, stylets such as stylet 320 areonly one example of how slotted stiffening members may be implemented tofacilitate insertion of an electrode lead into a cochlea of a patient.In other implementations, slotted stiffening members may be implementedin ways other than stylets such as stylet 320. For example, a stiffeningmember may be implemented as a stiffening sleeve permanently overmoldedalong a portion of an electrode lead so as to remain integrated with theelectrode lead after a surgical insertion of the electrode lead into acochlea of a patient.

To illustrate, FIG. 5 shows an exemplary electrode lead assembly 500including an electrode lead and a slotted stiffening member implementedas a stiffening sleeve permanently overmolded along a portion of theelectrode lead. FIG. 5 illustrates electrode lead assembly 500 in asubstantially linear configuration such as electrode lead assembly 500may be in prior to an insertion procedure in which electrode leadassembly 500 is inserted into a cochlea of a patient. Electrode leadassembly 500 includes various similar aspects and components aselectrode lead assembly 300 described above and, as such, these aspectsand components are numbered with corresponding reference numbers.Specifically, electrode lead assembly includes an electrode lead 502, adistal portion 504 of which is depicted in FIG. 5. Distal portion 504 ofelectrode lead 502 includes a distal tip 506, and, as with electrodelead assembly 300, it will be understood that a proximal portion 508 ofelectrode lead 502 is not explicitly illustrated but is represented byan omission symbol shown at a most proximal point on the portion ofelectrode lead 502 illustrated in FIG. 5.

Electrode lead 502 further includes an elongate lead body 510 having afirst side and a second side opposite the first side, as labeled in FIG.5. Along the first side of lead body 510, a plurality of electrodes 512are shown to be disposed, including a most distal electrode 514 (e.g., amost apical electrode) and most proximal electrode 516 (e.g., a mostbasal electrode).

While electrode lead assembly 300 was shown in FIG. 3 to include a lumen318 configured to encapsulate a stylet-type implementation of a slottedstiffening member, electrode lead assembly 500 does not include acorresponding lumen because electrode lead assembly 500 is supported bya different type of slotted stiffening member implementation. Forexample, electrode lead 502 may be a long lateral wall type electrodelead (e.g., an electrode lead that is longer than 27 millimeters and isconfigured to be inserted relatively deep into the patient's cochleacompared to certain other types of electrode leads). As such, electrodelead 502 may include two different portions 518 (e.g., a sleeved portion518-1 and an unsleeved portion 518-2) differentiated by whether or noteach is encapsulated by an implementation of a slotted stiffening membershown in FIG. 5 as a stiffening sleeve 520. As shown, stiffening sleeve520 extends along sleeved portion 518-1 for part of distal portion 504and the entire proximal portion 508 of electrode lead 502, whileunsleeved portion 518-2 includes the most distal part of distal portion504 (e.g., possibly including one or more of the most distal electrodes512).

In certain examples, such as for long lateral wall type electrode leadsconfigured to be inserted deeply into narrow and delicate apicalportions of the cochlea, it may be desirable for a most distal portionof the electrode lead to be more flexible and soft than may be the casefor shorter electrode leads that are not configured to be inserted sodeeply into the cochlea. As such, unsleeved portion 518-2 may be veryflexible as it is unsupported by any type of stiffening member. At thesame time, such long electrode leads may need a relatively great amountof support at a more proximal portion (e.g., to support the relativelylarge weight and/or leveraged force that may be applied to the longelectrode lead). As such, a relatively stiff stiffening sleeve 520 (orat least a stiffening sleeve 520 implementing a stiffness profileincluding certain regions that are relatively stiff) may be used toprovide support along sleeved portion 518-1.

As shown in FIG. 5, stiffening sleeve 520 may include an elongate body522 having a first side and a second side opposite the first side andconfigured to act as a stiffening sleeve for sleeved portion 518-1(e.g., by being permanently overmolded along sleeved portion 518-1) soas to maintain electrode lead 502 in a substantially linearconfiguration in an absence of a flexure force on body 522. The firstside of body 522 corresponds to the first side of electrode lead 502and, as such, is configured to be closer to electrodes 512 than thesecond side of body 522 while body 522 is integrated with (e.g.,permanently overmolded along) sleeved portion 518-1 of electrode lead502.

As with body 322 of stylet 320 described above, body 522 of stiffeningsleeve 520 may be constructed of any suitable material with any suitableplasticity limits. For instance, in some implementations, body 522 ofstiffening sleeve 520 may be constructed of a material that willplastically deform as body 522 flexes in the presence of a flexureforce. In other implementations, body 522 of stiffening sleeve 520 maybe constructed of a material that does not plastically deform (e.g.,does not reach a limit of plasticity) as a result of an inward flexingof body 522 due to the presence of the flexure force, even whenstiffening sleeve 520 is inwardly flexed to a relatively large angle ofdeflection. As with stylet 320, any of various suitable materials may beused to construct stiffening sleeve 520, such as a surgical gradestainless steel material, a polymer material, or the like.

As shown in FIG. 5, stiffening sleeve 520 may include a plurality ofcompression slots 524 distributed along the first side of body 522, anda plurality of strain relief slots 526 distributed along the second sideof body 522. The plurality of compression slots 524 may be configured tocompress, in a presence of the flexure force, so as to bias body 522 toflex in an inward direction as described above with body 322 of stylet320. At the same time, the plurality of strain relief slots 526 may beconfigured to expand, in the presence of the flexure force, so as tocomplement the plurality of compression slots 524 in biasing body 522 toflex in the inward direction. Slots 524 and 526 may be formed in any ofthe ways described herein or in any manner as may serve a particularimplementation. Additionally, the plurality of compression slots 524 andthe plurality of strain relief slots 526 may be distributed along thefirst and second sides of the body, respectively, in respective uniformor non-uniform distributions corresponding to any uniform or non-uniformstiffness profile as may serve a particular implementation. As describedabove in relation to the slots in stylet 320, slots 524 and 526 ofstiffening sleeve 520 may also include slots that all have identicalcharacteristics (e.g., slot size, slot type, etc.) or slots that havevarying characteristics to implement a non-uniform stiffness profile.

Whether a slotted stiffening member is implemented as a stylet (e.g.,such as stylet 320), as a stiffening sleeve (e.g., such as stiffeningsleeve 520), or in some other suitable form, respective compressionslots and strain relief slots distributed along the slotted stiffeningmember may function to guide, direct, allow, and/or otherwise bias abody of the slotted stiffening member to flex in a certain direction andwith a certain degree of flexibility by compressing and/or expanding inthe presence of a particular flexure force.

To illustrate, FIG. 6A shows a plurality of exemplary compression slotsand a plurality of exemplary strain relief slots distributed along abody of an exemplary slotted stiffening member while the body is in asubstantially linear configuration 600-A in an absence of a flexureforce on the body, while FIG. 6B shows the same pluralities ofcompression slots and strain relief slots while the body is in a flexedconfiguration 600-B in a presence of the flexure force on the body.Specifically, in FIG. 6A, a portion of a body 602 of a slottedstiffening member (e.g., such as stylet 320 or stiffening sleeve 520described above) is shown to include a plurality of unflexed (e.g.,uncompressed) compression slots 604-A and a complementary plurality ofunflexed (e.g., unexpanded) strain relief slots 606-A while no flexureforce is applied to body 602. In FIG. 6B, the portion of body 602 isshown with a plurality of flexed (e.g., compressed) compression slots604-B and a complementary plurality of flexed (e.g., expanded) strainrelief slots 606-B when the flexure force is applied to body 602.

Compression slots 604 (e.g., compression slots 604-A or 604-B dependingon whether a flexure force is applied to body 602) and strain reliefslots 606 (e.g., strain relief slots 606-A or 606-B depending on whetherthe flexure force is applied to body 602) may flex (e.g., compress orexpand) in any manner and/or may take any form as may serve a particularimplementation. For example, FIGS. 7A through 7D illustrate a fewexemplary pluralities 700 (e.g., pluralities 700-A through 700-D,respectively) of compression slots and strain relief slots that may beincluded on a slotted stiffening member (e.g., such as stylet 320 orstiffening sleeve 520) in different implementations. As in FIG. 6A, ineach plurality 700 of compression and strain relief slots in FIGS. 7Athrough 7D, compression slots are illustrated on the bottom while strainrelief slots are illustrated on the top (e.g., such that an “inward”flexing would involve the ends of each respective slotted stiffeningmember portion flexing toward the bottom of the page).

In each example illustrated in FIGS. 7A through 7D, strain relief slotsare shown to complement corresponding compression slots in a one-to-onemanner where one strain relief slot is positioned above a midpointbetween two adjacent compression slots. This may be an effective way forthe strain relief slots to complement the biasing of the stiffeningmember body performed by the compression slots. However, it will beunderstood that this is not the only type of configuration by whichstrain relief slots may complement compression slots. For example,rather than a one-to-one relationship between compression slots andstrain relief slots, there may be two or more compression slots forevery one strain relief slot in certain examples, or only onecompression slots for every two or more strain relief slots in otherexamples. As such, each strain relief slot may be disposed in anysuitable location with respect to the one or more compression slots towhich the strain relief slot corresponds (i.e., which the strain reliefslot is configured to complement) as may serve a particularimplementation.

In certain examples, as illustrated specifically in FIGS. 7A and 7B,compression slots may be different from their corresponding strainrelief slots such as by being larger, differently shaped, more complex,or the like. For example, as illustrated by pluralities 700-A and 700-B,at least some of the compression slots in the pluralities are differentin at least one of a slot size and a slot type from complementary strainrelief slots in the pluralities. As used herein, such compression slotsand strain relief slots may be referred to as “asymmetrical” to oneanother. Asymmetrical pluralities of compression and strain relief slotssuch as pluralities 700-A and 700-B may be advantageous in certainexamples because they may bias a slotted stiffening member to flex onlyin an inward direction (e.g., while restricting the stiffening memberfrom flexing in an outward direction opposite the inward directionand/or in any lateral direction).

In other examples, as illustrated specifically in FIGS. 7C and 7D,compression slots may be similar or identical to their correspondingstrain relief slots (e.g., albeit in an inverse orientation) such as bysharing the same slot type, slot size, and/or other suchcharacteristics. For example, as illustrated by pluralities 700-C and700-D, at least some of the compression slots in the pluralities areequivalent in a slot size and a slot type with complementary strainrelief slots in the pluralities. As used herein, such compression slotsand strain relief slots may be referred to as “symmetrical” to oneanother. Symmetrical pluralities of compression and strain relief slotssuch as pluralities 700-C and 700-D may be advantageous in certainexamples because they may bias a slotted stiffening member to flexeither in an inward direction or in an outward direction opposite theinward direction (e.g., while still restricting the stiffening memberfrom flexing in any lateral direction). In other words, due to thesymmetry in compression slots and strain relief slots in these examples,each slot may act as a compression slot when the stiffening memberflexes in one direction while acting as a strain relief slot when thestiffening member flexes in the opposite direction. Thus, when flexingin the outward direction (e.g., where both ends of each portion of thestiffening members flex toward the top of the page), the strain reliefslots distributed along the top of the body may essentially switch intocompression slots while the compression slots distributed along thebottom of the body may essentially switch into strain relief slots.

Either asymmetrical or symmetrical pluralities of compression and strainrelief slots may, in certain examples, include spring-back features tohelp control flexibility of the stiffening member body during differentphases of flexing motion. For example, at least some of the compressionslots in a plurality of compression slots may be spring-back cutsconfigured to mechanically provide a first degree of stiffness during aninitial phase of a flexing motion and a second degree of stiffnessduring a subsequent phase of the flexing motion, where the second degreeof stiffness is greater than the first degree of stiffness.

Returning to FIGS. 6A and 6B, configurations 600-A and 600-B illustratehow exemplary spring-back features may operate with “mushroom-shaped”spring-back compression slots such as compression slots 604. It will beunderstood that the spring-back principles described in relation tocompression slots 604 may similarly apply to any of the compressionslots in the pluralities of slots 700 in FIGS. 7A through 7D. As shownon one of the compression slots 604 in FIG. 6A, various contact points608 do not contact corresponding contact points 610, allowing thecompression slot 604 to compress with a relatively low degree ofstiffness (i.e., a relatively high degree of flexibility) during aninitial phase of a flexing motion (e.g., when body 602 is initiallyflexed out of substantially linear configuration 600-A toward flexedconfiguration 600-B). However, as shown on the same compression slot 604in FIG. 6B, contact points 608 may each make physical contact withcorresponding contact points 610 in flexed configuration 600-B, thusforcing compression slot 604 to have a higher degree of stiffness (i.e.,a lower degree of flexibility) if it is to compress further during asubsequent phase of a flexing motion (e.g., when body 602 has alreadyflexed to a desirable angle of deflection).

A flexure force causing substantially linear configuration 600-A to flexinto flexed configuration 600-B may originate from any of varioussources. For example, a flexure force on a body of a slotted stiffeningmember may be present as a result of contact between tissue of a cochleaof a patient and the slotted stiffening member or another part of anelectrode lead assembly of which the slotted stiffening member is apart. For example, the flexure force may originate from contact betweencochlear tissue and a portion of the electrode lead integrated with thebody of the stiffening member. As another example, a flexure force onthe body of a slotted stiffening member may be present as a result oftension applied to a pull wire coupled with (e.g. welded to) a distaltip of the stiffening member, or as a result of another suitable forceapplied in another way as may serve a particular implementation.

However, it will be understood that forces of gravity (e.g., gravity onthe stiffening member due to its own weight), fluid pressure (e.g., airpressure or cochlear fluid pressure during an insertion procedure or thelike), and/or other forces that may be present for a stiffening memberduring an insertion procedure prior to when it becomes desirable for thestiffening member to begin to flex (e.g., when a distal tip of theelectrode lead encounters a first turn within the cochlea), may not besufficient forces to be considered “flexure forces” as that term is usedherein. In other words, a slotted stiffening member may be stiff enoughto maintain substantially linear configuration 600-A when these variousminor forces are present, but may flex in the presence of a flexureforce such as from tissue contact, pull wire tension, or the like.

To illustrate, FIG. 8A depicts an implementation 300-A of electrode leadassembly 300 (i.e., the electrode lead assembly of FIG. 3 including theslotted stiffening member implemented as stylet 320) flexing under aflexure force present as a result of contact between tissue of a cochleaof a patient and an electrode lead integrated with the stiffening memberduring an exemplary insertion procedure. Specifically, as shown, theimplementation 300-A of electrode lead assembly 300 (“electrode leadassembly 300-A”) includes an electrode lead 302-A having a lumen 318-Ain which a stylet 320-A is encapsulated. It will be understood thatvarious aspects of electrode lead assembly 300 and/or components thereofthat are not specifically shown or labeled in FIG. 8A for clarity may bepresent and may function as described above in relation to electrodelead assembly 300.

Electrode lead assembly 300-A is being inserted into a cochlea 802 byway of an insertion procedure 804-A. At a moment during insertionprocedure 804-A depicted in FIG. 8A, electrode lead assembly 300-A(e.g., electrode lead 302-A in particular) has made physical contactwith tissue of cochlea 802, thus exerting a flexure force 806-A onelectrode-lead 302-A. In turn, flexure force 806-A is also shown to beresponsible for flexing stylet 320-A within lumen 318-A. As such, someof the compression slots on stylet 320-A have compressed and some of thestrain relief slots have expanded to bias the body of stylet 320-A toflex in the inward direction with an optimized degree of flexibilitythat does not cause trauma to the tissue of cochlea 802. Because stylet320-A guides and controls the flexing of electrode lead assembly 300-Ain this way, insertion procedure 804-A may be performed by a surgeon(e.g., by hand without robotic or computerized assistance) withoutspecial tools or equipment sometimes used to facilitate insertionprocedures. As the surgeon gently inserts electrode lead assembly 300-Ainto cochlea 802, stylet 320-A may gently direct the flexure ofelectrode lead assembly 300-A to conform to the curvature of cochlea 802without causing cochlear trauma such as a translocation.

As another example, FIG. 8B depicts a similar but differentimplementation 300-B of electrode lead assembly 300 flexing under aflexure force present as a result of tension applied to a pull wirecoupled with a distal tip of the stiffening member during an exemplaryinsertion procedure. Specifically, as shown, the implementation 300-B ofelectrode lead assembly 300 (“electrode lead assembly 300-B”) includesan electrode lead 302-B having a lumen 318-B in which a steerable stylet320-B is encapsulated. As with FIG. 8A above, it will be understood thatvarious aspects of electrode lead assembly 300 and/or components thereofthat are not specifically shown or labeled in FIG. 8B for clarity maystill be present and may function as described above.

Electrode lead assembly 300-B is being inserted into cochlea 802 by wayof an insertion procedure 804-B. At a moment during insertion procedure804-B depicted in FIG. 8B, electrode lead assembly 300-B has begun toflex even though it has not made physical contact with tissue of cochlea802. Instead, a flexure force 806-B is illustrated as a tension on apull wire 808 coupled (e.g., welded, etc.) to a distal tip of stylet320-B. As shown, when the tension is applied to pull wire 808 (e.g., bya surgeon performing insertion procedure 804-B using a tool thatfacilitates applying tension to pull wire 808), some of the compressionslots on stylet 320-B have compressed, some of the strain relief slotshave expanded, and the body of stylet 320-B has flexed in accordancewith the inward flex biasing implemented by the slots. Because pull wire808 may guide and control stylet 320-B to flex electrode lead assembly300-B in this way, insertion procedure 804-B may be performed by asurgeon (e.g., by hand without robotic or computerized assistance) usingminimal tools (e.g., a tool configured to facilitate applying tension topull wire 808). As the surgeon inserts electrode lead assembly 300-Binto cochlea 802, stylet 320-B may be steered using pull wire 808 toflex electrode lead assembly 300-B to conform to the curvature ofcochlea 802 without causing cochlear trauma such as a translocation.Indeed, in certain examples, the surgeon may steer electrode leadassembly 300-B into cochlea 802 with little or no contact at all betweenelectrode lead assembly 300-B and the tissue of cochlea 802. Activesteering of electrode lead assembly 300-B into cochlea 802 by way ofinsertion procedure 804-B may be based on pre-planning or any suitabletype of intraoperative monitoring or feedback. In some examples, asurgeon may perform insertion procedure 804-B, including activelysteering stylet 320-B, using only one hand.

As insertion procedures such as insertion procedures 804-A or 804-B areperformed using stylets encapsulated within respective lumens ofelectrode lead assemblies to control the flexing of the electrode leadassemblies, it is important for the stylets to remain properly orientedwithin the lumens. For example, if a stylet were to twist or rotate sothat the first side of the stylet (i.e., the side on which thecompression slots are disposed) is no longer facing the first side ofthe electrode lead (i.e., the side on which the electrodes aredisposed), the electrode lead assembly may flex in undesirabledirections and/or the insertion procedure may otherwise be compromised.Accordingly, it may be desirable to ensure that a unidirectional orbidirectional manner in which a stylet is biased to flex remain alignedwith how a surgeon desires an electrode lead encapsulating the stylet toflex.

To this end, a stiffening member such as a stylet (or a stiffeningsleeve that is not permanently overmolded along an electrode lead) mayby constructed to include an orientation retainer coupled to the body ofthe stiffening member at a proximal end of the body. As such, the firstside of the body may be configured to remain closer to the electrodesthan the second side (i.e., remain properly aligned as described above)while the body is integrated with the electrode lead due to aninterfacing of the orientation retainer with the electrode lead.

To illustrate, FIG. 9A depicts an exemplary orientation retainer coupledto the body of an exemplary slotted stiffening member at a proximal endof the body. Specifically, FIG. 9A illustrates a proximal end of anexemplary stylet 900 that includes a body 902 and is coupled to anorientation retainer 904, implemented as a mechanical feature configuredto interface with a body of an electrode lead. While compression slotsand strain relief slots are not illustrated on body 902 of stylet 900,it will be understood that such slots may be disposed on the first andseconds sides, respectively, on a distal portion of stylet 900 notexplicitly shown (e.g., as illustrated in relation to other styletsabove).

FIG. 9B illustrates orientation retainer 904 interfacing with anexemplary electrode lead to maintain a first side of body 902 of stylet900 to be closer to electrodes of the electrode lead than a second sideopposite the first side. Specifically, orientation retainer 904 isseated, connected, mated, attached, or otherwise interfaced at aninterface location 906 with a body of an electrode lead 908. Whileorientation retainer 904 is illustrated to be able to slide along thebody of electrode lead 908 to some degree, it will be understood thatother features of electrode lead 908 may, in some implementations, holdorientation retainer 904 in place so that interface location 906 remainsat a static position on the lead body. Additionally, while one type oforientation retainer and lead body are illustrated in FIGS. 9A and 9B,it will be understood that various other suitable designs for retainingthe orientation of the first and second sides of body 902 of stylet 900with respect to electrode lead 908 may be employed as may serve aparticular implementation.

In the preceding description, various exemplary embodiments have beendescribed with reference to the accompanying drawings. It will, however,be evident that various modifications and changes may be made thereto,and additional embodiments may be implemented, without departing fromthe scope of the invention as set forth in the claims that follow. Forexample, certain features of one embodiment described herein may becombined with or substituted for features of another embodimentdescribed herein. The description and drawings are accordingly to beregarded in an illustrative rather than a restrictive sense.

What is claimed is:
 1. A stiffening member comprising: a body configuredto integrate with a portion of an electrode lead so as to maintain theportion of the electrode lead in a substantially linear configuration inan absence of a flexure force on the body; a plurality of slotsdistributed along the body and configured to bias the body, in apresence of the flexure force, to flex inwardly on a first side of thebody, wherein the first side of the body closer is to a plurality ofelectrodes on the electrode lead than is a second side of the bodyopposite the first side; and an orientation retainer coupled to the bodyand configured to interface with the electrode lead to maintain, whilethe body is integrated with the portion of the electrode lead, the firstside of the body closer to the plurality of electrodes than the secondside of the body.
 2. The stiffening member of claim 1, wherein: theelectrode lead is included within a cochlear implant system and isconfigured for operation within a cochlea of a patient; and thestiffening member is implemented as a stylet configured to betemporarily encapsulated in a lumen of the electrode lead so as to beremovable from the lumen after a surgical insertion of the electrodelead into the cochlea of the patient.
 3. The stiffening member of claim1, wherein: the electrode lead is included within a cochlear implantsystem and is configured for operation within a cochlea of a patient;and the stiffening member is implemented as a stylet configured to bepermanently encapsulated in a lumen of the electrode lead so as toremain encapsulated in the lumen after a surgical insertion of theelectrode lead into the cochlea of the patient.
 4. The stiffening memberof claim 1, wherein the plurality of slots includes a plurality ofcompression slots distributed along the first side of the body, theplurality of compression slots configured to compress, in the presenceof the flexure force, so as to bias the body to flex inwardly on thefirst side.
 5. The stiffening member of claim 1, wherein the pluralityof slots includes a plurality of strain relief slots distributed alongthe second side of the body, the plurality of strain relief slotsconfigured to expand, in the presence of the flexure force, so as tobias the body to flex inwardly on the first side.
 6. The stiffeningmember of claim 1, wherein the plurality of slots includes: a pluralityof compression slots distributed along the first side of the body, theplurality of compression slots configured to compress, in the presenceof the flexure force, so as to bias the body to flex inwardly on thefirst side; and a plurality of strain relief slots distributed along thesecond side of the body, the plurality of strain relief slots configuredto expand, in the presence of the flexure force, so as to complement theplurality of compression slots in biasing the body to flex inwardly onthe first side.
 7. The stiffening member of claim 6, wherein at leastsome of the compression slots of the plurality of compression slotsdistributed along the first side of the body are different in at leastone of slot size or slot type from complementary strain relief slots ofthe plurality of strain relief slots distributed along the second sideof the body.
 8. The stiffening member of claim 6, wherein at least someof the compression slots of the plurality of compression slotsdistributed along the first side of the body are equivalent in both slotsize and slot type with complementary strain relief slots of theplurality of strain relief slots distributed along the second side ofthe body.
 9. The stiffening member of claim 1, wherein the plurality ofslots are distributed along the body in a non-uniform distribution inaccordance with a predetermined stiffness profile.
 10. The stiffeningmember of claim 1, wherein the plurality of slots are distributed alongthe body in a uniform distribution corresponding to a uniform stiffnessprofile.
 11. The stiffening member of claim 1, wherein the plurality ofslots implements a predetermined stiffness profile by including at leastone of: slots of different slot sizes on the first side of the body, orslots of different slot types on the first side of the body.
 12. Thestiffening member of claim 1, wherein: the body of the stiffening memberis constructed of a material that does not plastically deform as aresult of an inward flexing of the body due to the presence of theflexure force; and the body is configured to return, after the inwardflexing, to the substantially linear configuration upon removal of theflexure force causing the inward flexing.
 13. The stiffening member ofclaim 1, further comprising a pull wire coupled with a distal tip of thestiffening member; wherein the flexure force on the body is present as aresult of tension applied to the pull wire.
 14. An electrode leadassembly comprising: an electrode lead with a plurality of electrodes;and a stiffening member configured to integrate with a portion of theelectrode lead so as to maintain the portion of the electrode lead in asubstantially linear configuration in an absence of a flexure force on abody of the stiffening member, wherein the stiffening member includes: aplurality of slots distributed along the body and configured to bias thebody, in a presence of the flexure force, to flex inwardly on a firstside of the body, wherein the first side of the body closer is to theplurality of electrodes on the electrode lead than is a second side ofthe body opposite the first side; and an orientation retainer coupled tothe body and configured to interface with the electrode lead tomaintain, while the body is integrated with the portion of the electrodelead, the first side of the body closer to the plurality of electrodesthan the second side of the body.
 15. The electrode lead assembly ofclaim 14, wherein the plurality of slots includes a plurality ofcompression slots distributed along the first side of the body, theplurality of compression slots configured to compress, in the presenceof the flexure force, so as to bias the body to flex inwardly on thefirst side.
 16. The electrode lead assembly of claim 14, wherein theplurality of slots includes a plurality of strain relief slotsdistributed along the second side of the body, the plurality of strainrelief slots configured to expand, in the presence of the flexure force,so as to bias the body to flex inwardly on the first side.
 17. Theelectrode lead assembly of claim 14, wherein the plurality of slotsincludes: a plurality of compression slots distributed along the firstside of the body, the plurality of compression slots configured tocompress, in the presence of the flexure force, so as to bias the bodyto flex inwardly on the first side; and a plurality of strain reliefslots distributed along the second side of the body, the plurality ofstrain relief slots configured to expand, in the presence of the flexureforce, so as to complement the plurality of compression slots in biasingthe body to flex inwardly on the first side.
 18. A stylet comprising: abody that is constructed of a material that does not plastically deformas a result of an inward flexing of the body and that is configured tobe encapsulated within a lumen of an electrode lead so as to maintainthe electrode lead in a substantially linear configuration in an absenceof a flexure force on the electrode lead; a plurality of slotsdistributed along the body and configured to bias the body, in apresence of the flexure force, to flex inwardly on a first side of thebody, wherein the first side of the body closer is to a plurality ofelectrodes on the electrode lead than is a second side of the bodyopposite the first side; and an orientation retainer coupled to the bodyand configured to interface with the electrode lead to maintain, whilethe body is encapsulated within the lumen, the first side of the bodycloser to the plurality of electrodes than the second side of the body.19. The stylet of claim 18, wherein the plurality of slots includes aplurality of compression slots distributed along the first side of thebody, the plurality of compression slots configured to compress, in thepresence of the flexure force, so as to bias the body to flex inwardlyon the first side.
 20. The stylet of claim 18, wherein the plurality ofslots includes a plurality of strain relief slots distributed along thesecond side of the body, the plurality of strain relief slots configuredto expand, in the presence of the flexure force, so as to bias the bodyto flex inwardly on the first side.